The present invention relates to a method and apparatus for elevating, and stretching a collapsible screen, provided with a stiffening upper frame, which screen is supported on a vehicle such as a tank having a gun barrel or the like.
A collapsible screen which can be raised is utilized, for tanks which at their upper parts are provided with a storage space for the screen which attends around the vehicle. The collapsible screen can temporarily be raised when, from its stored position when the tank is to be moved in or upon water so that it becomes desirable to increase the displacement of the vehicle.
The collapsible screen, which usually is made with a rectangular cross section with dimensions of 10 .times. 5 meters, has a height of 1 or a few meters in its raised position, and the cloth in the screen, which is waterproof, can have a thickness of 0.5 - 5.0 mm. A collapsible screen which is suitable for use with the present invention is described in the Swedish Pat. No. 226.690.
Because of the large dimensions of the collapsible screen, problems may be encountered in achieving rapid and efficient raising of the screen when using prior art methods and apparatus. The raising also is often made more difficult due to the fact that it must often be carried out under extremely poor light and weather conditions.